Automatic shut-off valve



Patented Sept. 13, 1932 UNITED STATES PATENT OFFICE.

GEORGE IR. BROWN AND GEORGE E. NAAIB, OF CLEVELAND, OHIO, ASSIGNORS TO THE NORTH AMERICAN MANUFACTURING COMPANY, OF CLEVELAND, OHIO, A CORPORA- TION OF OHIO AUTOMATIC SHUT-OFF VALVE Application filed March 14, 1932. Serial No. 598,757.

This invention relates to safety control devices of the type having an automatic shutoff valve and particularly adapted for controlling the fuel supply in combustion appliances such as oil and gas burners. This application is a continuation in part of our copending application, Serial No. 543,618, filed June 11, 1981.

In such a gas installation the burner is supplied with gas under slight pressure and air for combustion at a greater pressure, and since the mixture thereof is highly explosive, the two components are usually not allowed to commingle until they are as close as possible to the burner or manifold therefor.

If during operation there should be a failure of air it will be apparent that undiluted gas may find its way into and back through the air passage; and likewise should there be a failure of gas, air may find its way into the gas passage. In either case the result is that one of the supply lines contains an explosive mixture. Further, should the gas pressure fail and subsequently be renewed, explosive mixture will be fed to the burner without being there burned. For all of these reasons it is necessary to provide a shutoff valve in the gas line as close to the inlet as possible.

In a similar installation for burning other fuels such as oil, pulverized coal or the like, it will be apparent that an automatic shutoff valve in the fuel supply line is similarly desirable.

It is the object of the present invention to provide'such a valve which will automatically close upon failure of pressure in either the air or the fuel line.

A further object is to arrange for adjustment of the parts to provide for such operation under difierent fluid, pressure conditions.

The exact nature of this invention together with further objects and advantages thereof will be apparent from the following description taken in connection with the accompanying drawing in which Figs. 1 and 2 are side and end views of an embodiment of the invention, Fig. 1 being largely in section, with parts broken away to show details of construction.

With reference now to the drawing, 1 is a valve body within which is the usual seat and avalve therefor, which valve has a stem 2 pro ect1ng upwardly of the valve body for sliding bearing in a frame 3 rigidly associated with the body. The valve stem includes an apertured part 4 to receive a lever arm 5. This lever arm is fulcrumed upon the link 6 at one end, carries a weight 7 at its opposite end, and intermediate its ends bears upon the valve stem, the arrangement being obviously one whereby the weight 7 has effect to lower the valve to closed position. A slotted guide post 8 serves to relieve the valve stem of side thrust. What has thus far been described is not new in the art.

According to this invention latch means are provided for releasably securing the valve in open position. For this purpose a collar 9 having an annular groove 10 is secured upon the valve stem 2, and a cooperative plunger 11 is mounted in the frame 3. The plunger has a nose 12 engageable in the groove 10 by movement of the plunger toward the valve stem 2, but the plunger is yieldably urged from engaging position by spring means as at 13 effective upon its head 14.

It will be apparent that with the parts as in Fig. 1, the plunger 11 being positioned by the spring 13 to clear the collar 9, the valve will drop from the position of Fig. 1 which is its open position, to closed position, under the action of the weight 7. But if the plunger 11 be depressed against the spring 13, so that the nose 12 engages the groove 10, the valve would be held in open position, that indicated Fig. 1, against the action of the weight 7. For conditionally maintaining the plunger 11 in valve retaining position, dependent upon the maintenance of a plurality of fluid pressures, a plurality of pressure-responsive means are associated with the plunger.

A diaphragm housing 15 is mounted upon an extension 3a of the frame 3, and contains a diaphragm 16. This diaphragm is secured with a hollow push rod 17 which extends to a position adjacent the plunger head 14. A spring 18 backed by a stop 19 is arranged to yieldably urge the diaphragm 16 from the plunger 11. The pushrod 17 bears in the stop 19, which in turn is threaded into the frame part 3a whereby the spring 18 may be adjusted. A lock nut 20 is provided for maintaining such adjustment.

The opposite end of the push rod 17 extends, with a close fit, through the far side of the diaphragm housing, which latter has an inlet connection 21 whereby the diaphragm 16 may be responsive to fluid pressure in the adjacent chamber. A of the housing. ,The opposite chamber of the housing has connection with the atmosphere by way of the opening 22 through which the spring 18 extends.

It will be apparent that llllld pressure in the chamber A acts against the diaphragm 16, with tendency to move the plunger 11 into engagement with the collar 9.

A housing 23 for a sylphon bellows 24 1s rigidly associated with the diaphragm housing 15, by a spacer 25 of spider form. The bellows 24 is associated with the plunger 11 for effect upon the latter by a push rod 26 which extends through the hollow push rod 17 of the diaphragm 16. The bellows 24 is arranged for fluid pressure actuation by way of an inlet connection 27, and is urged from the plunger 11 by spring means 28 having a central opening to clear the push rod 26. The spring 28 is backed by a stop 29 made adjustable by threading into the member 25, provided with a lock nut 30, and having a central opening suflicient to clear the push rod 17 of the diaphragm.

It will be apparent that by this arrangement a fluid pressure transmitted through the connection 27 will be effective upon the plunger 11 to urge the latter toward the valve stem collar 9.

It will be apparent that two pressure rcsponsive elements have been described, one including the diaphragm 16 effective under fluid pressure in opposition to the spring 18, the other including the bellows 24 effective under fluid pressure in opposition to the spring 28; and both units having, responsive to fluid pressure, effect against the spring 13 and upon the valve, toward maintaining the latter open.

In service, one of these units will have connection with the fuel line in which the valve is located, and the other will have connection with the air line.

Thus operation will be as follows, considering the valve 1 as in a fuel line, the bellows 24 having connection with the fuel line on that side of the valve 1 toward the source of fuel supply, and the diaphragm chamber A connected with the line by which air is supplied to the burner in which combustion of the fuel is to take place: The springs 18 and 28 are adjusted by their stops 19 and 29, each to such a tension that the plunger 11 will maintain the valve open, against the action of the weight 7, only by the combined action of both pressure-rcsponsive units. Thus upon failure of pressure at either of the two sources to which these units are responsive, the spring 13 will overcome the effect of'the remaining pressure and the valve will close.

What we claim is:

1. In a valve control device of the class described, means balancing said valve toward closed position, and means for conditionally maintaining said valve in open position and including a plurality of units arranged to be responsiveto separate fluid pressures for independent effect-upon said valve toward maintaining the latter open, said units being togethercapable of so maintaining said valve, but each alone incapable of so maintaining said valve.

2. In a valve control device of the class described, means balancing said valve toward closed position, means for conditionally maintaining said valve in open position and including a plurality of units arranged to be responsive to separate fluid pressures for independent efl'ort toward maintaining said valve open, said units being together capable of so maintaining said valve, but each alone incapable of so maintaining said valve, and means for independent adjustment of said units to provide for such described operation under different fluid pressure conditions.

3. In a valve control device of the class described, means balancing said valve toward closed position, latch means for releasably maintaining said valve in open position, and a plurality of pressure responsive means associated with said latch means to provide release of said valve for closing dependent upon failure of pressure from any of a corresponding plurality of sources.

1. -In a valve control device of the class described, means balancing said valve toward signatures.

GEORGE R. BROWN. GEORGE F. NAAB. 

